welcome-file element to use a Struts action

It says in a book: "Because the web containers don't use the servlet mappings for resources in the welcome-filelist, you can't directly set up a welcome-file element to use a Struts action."

Maybe I misunderstood this statement, but I got the impression that we can't use struts action on the welcome file. But I put couple input text box and struts submit button on the welcome file and it still works. So what is going on?

I searched some more on the web, I guess my question is why would someone want to set index.do as an homepage. I think one of the explanation is that maybe some people want to hide index.html and not use it as the default page, which makes sense I suppose...

Tony: I am not sure what you are asking. I would rather have an action (welcome.do) as the "welcome-file" in my web.xml file, but my understanding is that this does not work. I suppose that I have never actually tried it out. So I have the file index.jsp that redirects to the action that displays the first page.